What we have here are several mailbox template pages, and some of the status pages that graced the system. The bright blue and white pages are from the initial public service. The ones with the sort of phallic arrow symbol are from the "New" mailbox service, launched in July 1989, complete with charges! Previously, sending messages had been free. (Although IPs had always paid to receive their response frames.)
I think the yellow 93a page was from the edit computer, Duke, based on the "Message services for IPs", and reflects the very old style of page that has a heading picked out in graphics.
One of the features of Prestel was, when using the official *90# method to sign off and disconnect, it would check to see if you had any messages waiting and if you did, present you with a warning and the option to read them.